Many studies have been made in refine transmission to improve the de-haze quality. Compared by several common method of refine transmission, we present an improved refine transmission method of secondary filter to improve halo effect in this paper. Halo effect area is determined by the difference between the estimate transmission and the transmission refined by guided filter. The transmission which is refined by guided filter in halo effect area is replaced by the transmission refined by median filter. Using this method, the too high transmission in halo effect area will be refined. The refine transmission method present by this paper, which combine the advantages of median filter algorithm and the guided filter algorithm. This method can avoid black spots caused by median filter algorithm and halo effect residues caused by guided filter algorithm.